Boring-machine



(No Model.)

B. FQALLEN;

BORING MAGHINE} No. 251,686. Patented Jan. 3 1882.

V B I 175 .5. yi Z3 5 m B .B

- UNITED STATE PATENT OFFICE.

BENJAMIN F. ALLEN, OF BOSTON, MASSACHUSETTS.

BORING-MACHINE. Q

SPECIFICATION forming part; of Letters Patent No. 251,686, dated January 3, 1882,

' Application filed October 6, 1881. (No model.)

To all whom it may concern: v Be it known that I, BENJAMIN F. ALLEN, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and use ful Improvements in Boring-Machines, ofwhich the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to an improvement in that class of boring-machines used for the purpose of forming tapering holes that enlarge as they increasein depth, thus giving a dovetailed section, which is of great utility in the operation commonly known as doweling, which consists in the uniting of two or more pieces of wood by pins that enter a part of their length into each piece.

In order to make a stronger joint, these pins are frequently provided with wedges in each end,which expand part of the pin and cause it to retain a much stronger hold upon the parts which it unites. Notwithstanding this, when the holes into which the pins enter are of the same diame'ter from end to end, and the material hard the pins are liable to be drawn outuudenheavy strains, to obviate which it has been proposed to enlarge the hole, which the pin enters, at its bottom, thus allowing the wedge to expand the pin more, and consequently give it a better hold upon the wood. Several devices have been invented for accomplishing this result; but so far as my knowledge extends none of them have gone into general use, owing to the complex nature of their construction, which rendered them slow in action and difticult to keep in repair.

My invention consists, essentially, in providing the boring-arbor with sleeve'bearings, which are so arranged as to throw the axis of the boring-arbor out of line radially with the axis of its journals, and in a boring-bit of peculiar construction, which, by means of the radial movement of the arbor, is caused to .fOIiil a hole larger at its extremity than at its point of entrance, all as will be hereinafter fully described, and then specifically pointed out in the claims.

In the accompanying drawings, Figure 1 is aside view, partly in section, of a machine embodying my improvements. Fig.2 is a vertical longitudinal section of the sleeve-journals and journal-boxes. Fig. 3 is a vertical transverse'scction of Fig. l-on the line we, and Fig. 4 is asimilar section on the line 3 y of Fig. 2

The bed-plate A of the machine may be of any proper form or construction suited to the special work the machine is to be employed upon, andcarries the journal-boxes B B, within which revolve the sleeve-journalsO 0. These journals are prevented from moving endwise the sleeved journals and-boring-arbor being made by attaching to the latter at diametricall y-opposite points two splines, b b, which enter grooves c 0, formed for their reception in the opposite sides of the internal surfaces of the sleeve-journals. The bottoms of these grooves and the outer surface of the splines are correspondingly inclined, so that when the boring-arbor is moved longitudinally it is given a radial movement with relation to the sleevejournal, thus allowing it, when drawn back into the position shown in Fig. 1, to have its axis coincident'with'that of the journal; but when thrownforward, as shown in Fig. 2, the axis of the arbor will be outside that of the journal, and will consequently describe a circle around it as they revolve. The boring-bit d is constructed as shown in Figs. 1 and 2, its outer end having a greater diameter than the shank which enters the arbor, its cutting part being thus brought to the general shape of a conical frustum. I

The operation of the machine is as follows: The boring-arbor is rotated by means of a belt running from the pulley E to any suitable motor. Devices are also connected wit-h the arbor by means of which a longitudinal movement can be imparted to it, and by which it is retained in the position shown in Fig. 1, its axis coincident with that of the sleeved journals when not in the act of boring. The material to be perforated is then placed in position, as at F, and the boring-arbor caused to advance. As at the commencement of this advance the axis of the borin g-arbor and sleeve journal coincide the boring-bit will enter the wood directly. but as it advances it is thrown out radially by the action of the inclined grooves and splines, and describes a circle around the axis of the sleeve-journal proportional to the distance it is moved from the central line. This causes the perforations to be enlarged, as shown in Fig. 2, and the outer end of the boring-bit having the greatest diameter, of course the inner end of the perforation is correspondingly enlarged. When the boring arbor and bit are withdrawn they follow the same course as when brought forward, the large end of the bit,when it arrives at the point where it first perforated the wood, revolvingupon the same axis as the sleeve-journal, passes out without enlarging theouter end of the hole,thus enabling the machine to bore'conical holes with the same rapidity as the ordinary cylindrical ones are bored, the machine by which it is accomplished being simple, durable, and cheaply construted.

Having thus described my invention, Iclaim 25 as new, and desire to secure by Letters Patent, the following:

1. The combination of the longitudinallymovable auger-shaft bearing a cone-shaped boring-tool with mechanism, substantially 0 such as described, for automatically moving it in a lateral direction simultaneously with its longitudinal movement, substantially as and for the purpose described. I

2. The boring-arbor D, provided with in- 3 5 clined splines b, in combination with the sleeve-journal 0, having inclined grooves 0, arranged and operating in the manner and for the purpose specified.

In testimony whereof I affix my signature 4c in presence'of two witnesses.

BENJ. F. ALLEN.

Witnesses E. CHANDLER, CHAS. A. WALTER, 

